Onomastics or onomatology is the study of the origin, history, and use of proper names.Onomastics originates from the Greek ὀνομαστικός (onomastikós), which translates to "of or belonging to naming", from ὄνομα (ónoma) meaning "name".Toponymy or toponomastics, the study of place names, is one of the principal branches of onomastics. Anthroponomastics is the study of personal names. Onomastics can be helpful in data mining, with applications such as named-entity recognition, or recognition of the origin of names.Literary onomastics is the branch that researches the names in works of literature and other fiction. An orthonym is the proper name of the object in question, the object of onomastic study.
The Portuguese writer and poet Fernando Pessoa explores onomastics in a literary setting through his invention of the heteronym.